A shut reactor restarted for data centres
On 20 September 2024 Constellation announced a 20-year agreement with Microsoft to buy power from the Crane Clean Energy Center - Unit 1 of the Three Mile Island plant, shut for economic reasons exactly five years earlier to the day. The unit is to add about 835 MW of carbon-free capacity to the grid; the restart is expected in 2028.
Why it matters
Demand from data centres had already been changing which power stations get built. Here it changed, for the first time, which ones get closed: a unit the market had written off as unprofitable is being returned to service under a single long-term contract. The price of computation began to be measured partly in what it keeps from leaving the grid.
It is the largest power purchase agreement in the company's history by its own account. Under a separate request it intends to renew the unit's operating licence to at least 2054. The turbine, the generator, the main transformer and the cooling and control systems all have to be restored; the restart requires approval from the United States Nuclear Regulatory Commission and permits from state and local agencies. The 3,400 direct and indirect jobs, the 16 billion dollars added to state GDP and the more than 3 billion in taxes are figures from a Brattle Group study commissioned by the Pennsylvania Building and Construction Trades Council, not the company's own calculation. Unit 1 is a fully independent facility; Unit 2, where the 1979 accident happened, is being decommissioned by a different owner. What the record does not claim. The press release carries no project cost of 1.6 billion dollars, and no statement that the buyer contracted 100 per cent of the plant's output: the strings 1.6 billion and 100 per cent occur on the page zero times.